HOP IN THE SPOTLIGHT: New frog species discovered in PH after 20 years of misidentification

After spending twenty years under the wrong name and mistaken for another species, the fanged frog Limnonectes cassiopeia has finally hopped into the spotlight, claiming its identity as a distinct species within the rich biodiversity of the Philippines' ecosystems.

This newly discovered frog, now known to be endemic in the country, has fooled scientists all along.

Researchers from the University of Kansas announced this finding in the Journal Ichthyology & Herpetology, revealing that the frog lives on the island of Luzon.

Despite being collected more than a dozen times in the past two decades, these specimens were wrongly identified as young versions of the Luzon Giant Toothed Frog.

“The giant toothed frog was not recognized in the Philippines because it looked almost identical to the larger species,” Mark Herr, a doctoral student at KU's Biodiversity Institute and Natural History Museum, said.

However, through genetic sequencing and detailed measurements, Herr found subtle differences, notably the new species’ pale, unpigmented toe discs—significantly smaller and white compared to the larger, dark gray toe pads of Limnonectes macrocephalus. This discovery was the key to differentiating the two species.

Fortunately, extensive work in the Philippines by Herr's KU faculty mentor, Rafe Brown, and previous generations of KU researchers provided plenty of specimens at the KU Biodiversity Institute and Natural History Museum.

“I validated my genetic work to make sure there were no errors, and there were none,” Herr said.

He examined all the Limnonectes specimens from Luzon in the museum, comparing the 19 that appeared in the new genetic cluster with those in the main cluster.

Despite being collected multiple times over the years, it took Herr’s meticulous genetic study to officially separate Limnonectes cassiopeia from its close relative. He named the species after the constellation Cassiopeia, referencing the five white toe pads resembling the star pattern.

“It’s easy to understand how they could be confused as the same species,” Herr said.

With Limnonectes cassiopeia now identified, Herr is eager to study its behavior in the wild and understand how it is different from Limnonectes macrocephalus.

“Now that we know they’re different, we can go out and watch them and study their natural history,” he said.

The world has now met its new friend–once unknown, the Limnonectes cassiopeia has now hopped in to its own spotlight–through the help of scientists who have combed our diverse forests to seek its true knowledge.